diff --git a/static/js/realm_user_settings_defaults.ts b/static/js/realm_user_settings_defaults.ts
index cd2a1104fd..dbaeab0753 100644
--- a/static/js/realm_user_settings_defaults.ts
+++ b/static/js/realm_user_settings_defaults.ts
@@ -32,6 +32,7 @@ export type RealmDefaultSettingsType = {
     realm_name_in_notifications: boolean;
     starred_message_counts: boolean;
     translate_emoticons: boolean;
+    display_emoji_reaction_users: boolean;
     twenty_four_hour_time: boolean;
     wildcard_mentions_notify: boolean;
 };
diff --git a/static/js/server_events_dispatch.js b/static/js/server_events_dispatch.js
index 5f4a0a9d87..bbb316fca4 100644
--- a/static/js/server_events_dispatch.js
+++ b/static/js/server_events_dispatch.js
@@ -606,6 +606,7 @@ export function dispatch_normal_event(event) {
                 "timezone",
                 "twenty_four_hour_time",
                 "translate_emoticons",
+                "display_emoji_reaction_users",
                 "starred_message_counts",
                 "send_stream_typing_notifications",
                 "send_private_typing_notifications",
@@ -686,6 +687,10 @@ export function dispatch_normal_event(event) {
                 // Rerender buddy list status emoji
                 activity.build_user_sidebar();
             }
+
+            if (event.property === "display_emoji_reaction_users") {
+                message_live_update.rerender_messages_view();
+            }
             if (event.property === "escape_navigates_to_default_view") {
                 $("#go-to-default-view-hotkey-help").toggleClass("notdisplayed", !event.value);
             }
diff --git a/static/js/settings_config.ts b/static/js/settings_config.ts
index 5406695afc..98a2031c44 100644
--- a/static/js/settings_config.ts
+++ b/static/js/settings_config.ts
@@ -496,6 +496,12 @@ export const display_settings_labels = {
             defaultMessage: "Convert emoticons before sending (<code>:)</code> becomes 😃)",
         }),
     ),
+    display_emoji_reaction_users: new Handlebars.SafeString(
+        $t_html({
+            defaultMessage:
+                "Display names of reacting users when few users have reacted to a message.",
+        }),
+    ),
     escape_navigates_to_default_view: $t({defaultMessage: "Escape key navigates to default view"}),
 };
 
diff --git a/static/js/user_settings.ts b/static/js/user_settings.ts
index bb6bbff0fc..31228c2dd5 100644
--- a/static/js/user_settings.ts
+++ b/static/js/user_settings.ts
@@ -32,6 +32,7 @@ export type UserSettingsType = {
     realm_name_in_notifications: boolean;
     starred_message_counts: boolean;
     translate_emoticons: boolean;
+    display_emoji_reaction_users: boolean;
     twenty_four_hour_time: boolean;
     wildcard_mentions_notify: boolean;
     send_stream_typing_notifications: boolean;
diff --git a/static/templates/settings/display_settings.hbs b/static/templates/settings/display_settings.hbs
index be80c97627..13fcccbbb0 100644
--- a/static/templates/settings/display_settings.hbs
+++ b/static/templates/settings/display_settings.hbs
@@ -73,6 +73,13 @@
           label=settings_label.translate_emoticons
           prefix=prefix}}
 
+        {{#if page_params.development_environment }}
+        {{> settings_checkbox
+          setting_name="display_emoji_reaction_users"
+          is_checked=settings_object.display_emoji_reaction_users
+          label=settings_label.display_emoji_reaction_users
+          prefix=prefix}}
+        {{/if}}
     </div>
 
     <div class="advanced-settings {{#if for_realm_settings}}org-subsection-parent{{else}}subsection-parent{{/if}}">
diff --git a/templates/zerver/api/changelog.md b/templates/zerver/api/changelog.md
index 2356c41e1f..d68b58d138 100644
--- a/templates/zerver/api/changelog.md
+++ b/templates/zerver/api/changelog.md
@@ -20,6 +20,14 @@ format used by the Zulip server that they are interacting with.
 
 ## Changes in Zulip 6.0
 
+**Feature level 125**
+
+* [`POST /register`](/api/register-queue), [`PATCH
+  /settings`](/api/update-settings), [`PATCH
+  /realm/user_settings_defaults`](/api/update-realm-user-settings-defaults):
+  Added new `display_emoji_reaction_users` display setting,
+  controlling whether to display the names of users with emoji reactions.
+
 Feature levels 123-124 are reserved for future use in 5.x maintenance
 releases.
 
diff --git a/version.py b/version.py
index 8d035cd474..6eabf0aa7f 100644
--- a/version.py
+++ b/version.py
@@ -33,7 +33,7 @@ DESKTOP_WARNING_VERSION = "5.4.3"
 # Changes should be accompanied by documentation explaining what the
 # new level means in templates/zerver/api/changelog.md, as well as
 # "**Changes**" entries in the endpoint's documentation in `zulip.yaml`.
-API_FEATURE_LEVEL = 122
+API_FEATURE_LEVEL = 125
 
 # Bump the minor PROVISION_VERSION to indicate that folks should provision
 # only when going from an old version of the code to a newer version. Bump
diff --git a/zerver/migrations/0389_userprofile_display_emoji_reaction_users.py b/zerver/migrations/0389_userprofile_display_emoji_reaction_users.py
new file mode 100644
index 0000000000..adb36da249
--- /dev/null
+++ b/zerver/migrations/0389_userprofile_display_emoji_reaction_users.py
@@ -0,0 +1,23 @@
+# Generated by Django 3.2.12 on 2022-04-16 13:45
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("zerver", "0388_preregistrationuser_created_user"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="realmuserdefault",
+            name="display_emoji_reaction_users",
+            field=models.BooleanField(default=True),
+        ),
+        migrations.AddField(
+            model_name="userprofile",
+            name="display_emoji_reaction_users",
+            field=models.BooleanField(default=True),
+        ),
+    ]
diff --git a/zerver/models.py b/zerver/models.py
index add7e67f6a..3d08ad3c78 100644
--- a/zerver/models.py
+++ b/zerver/models.py
@@ -1467,6 +1467,7 @@ class UserBaseSettings(models.Model):
     fluid_layout_width: bool = models.BooleanField(default=False)
     high_contrast_mode: bool = models.BooleanField(default=False)
     translate_emoticons: bool = models.BooleanField(default=False)
+    display_emoji_reaction_users: bool = models.BooleanField(default=True)
     twenty_four_hour_time: bool = models.BooleanField(default=False)
     starred_message_counts: bool = models.BooleanField(default=True)
     COLOR_SCHEME_AUTOMATIC = 1
@@ -1603,6 +1604,7 @@ class UserBaseSettings(models.Model):
         **notification_setting_types,
         **dict(
             # Add new general settings here.
+            display_emoji_reaction_users=bool,
             escape_navigates_to_default_view=bool,
             send_private_typing_notifications=bool,
             send_read_receipts=bool,
diff --git a/zerver/openapi/zulip.yaml b/zerver/openapi/zulip.yaml
index 9c0674792c..38b45dc831 100644
--- a/zerver/openapi/zulip.yaml
+++ b/zerver/openapi/zulip.yaml
@@ -7962,6 +7962,20 @@ paths:
           schema:
             type: boolean
           example: true
+        - name: display_emoji_reaction_users
+          in: query
+          description: |
+            Whether to display the names of reacting users on a message.
+
+            When enabled, clients should display the names of reacting users, rather than
+            a count, for messages with few total reactions. The ideal cutoff may depend on
+            the space available for displaying reactions; the official web application
+            displays names when <=3 total reactions are present with this setting enabled.
+
+            **Changes**: New in Zulip 5.0 (feature level 125).
+          schema:
+            type: boolean
+          example: false
         - name: default_view
           in: query
           description: |
@@ -9884,6 +9898,19 @@ paths:
                             description: |
                               Whether to [translate emoticons to emoji](/help/enable-emoticon-translations)
                               in messages the user sends.
+                          display_emoji_reaction_users:
+                            type: boolean
+                            description: |
+                              Whether to display the names of reacting users on a message.
+
+                              When enabled, clients should display the names of reacting
+                              users, rather than a count, for messages with few total
+                              reactions. The ideal cutoff may depend on the space
+                              available for displaying reactions; the official web
+                              application displays names when <=3 total reactions are
+                              present with this setting enabled.
+
+                              **Changes**: New in Zulip 5.0 (feature level 125).
                           default_language:
                             type: string
                             description: |
@@ -11648,6 +11675,19 @@ paths:
                             description: |
                               Whether to [translate emoticons to emoji](/help/enable-emoticon-translations)
                               in messages the user sends.
+                          display_emoji_reaction_users:
+                            type: boolean
+                            description: |
+                              Whether to display the names of reacting users on a message.
+
+                              When enabled, clients should display the names of reacting
+                              users, rather than a count, for messages with few total
+                              reactions. The ideal cutoff may depend on the space
+                              available for displaying reactions; the official web
+                              application displays names when <=3 total reactions are
+                              present with this setting enabled.
+
+                              **Changes**: New in Zulip 5.0 (feature level 125).
                           default_language:
                             type: string
                             description: |
@@ -12591,6 +12631,20 @@ paths:
           schema:
             type: boolean
           example: true
+        - name: display_emoji_reaction_users
+          in: query
+          description: |
+            Whether to display the names of reacting users on a message.
+
+            When enabled, clients should display the names of reacting users, rather than
+            a count, for messages with few total reactions. The ideal cutoff may depend on
+            the space available for displaying reactions; the official web application
+            displays names when <=3 total reactions are present with this setting enabled.
+
+            **Changes**: New in Zulip 5.0 (feature level 125).
+          schema:
+            type: boolean
+          example: false
         - name: default_language
           in: query
           description: |
diff --git a/zerver/views/realm.py b/zerver/views/realm.py
index c83fd6c8f5..6887e76edb 100644
--- a/zerver/views/realm.py
+++ b/zerver/views/realm.py
@@ -341,6 +341,7 @@ def update_realm_user_settings_defaults(
         json_validator=check_int_in(UserProfile.COLOR_SCHEME_CHOICES), default=None
     ),
     translate_emoticons: Optional[bool] = REQ(json_validator=check_bool, default=None),
+    display_emoji_reaction_users: Optional[bool] = REQ(json_validator=check_bool, default=None),
     default_view: Optional[str] = REQ(
         str_validator=check_string_in(default_view_options), default=None
     ),
diff --git a/zerver/views/user_settings.py b/zerver/views/user_settings.py
index 0b92dca7e3..3de690b335 100644
--- a/zerver/views/user_settings.py
+++ b/zerver/views/user_settings.py
@@ -146,6 +146,7 @@ def json_change_settings(
         json_validator=check_int_in(UserProfile.COLOR_SCHEME_CHOICES), default=None
     ),
     translate_emoticons: Optional[bool] = REQ(json_validator=check_bool, default=None),
+    display_emoji_reaction_users: Optional[bool] = REQ(json_validator=check_bool, default=None),
     default_language: Optional[str] = REQ(default=None),
     default_view: Optional[str] = REQ(
         str_validator=check_string_in(default_view_options), default=None